Sulfacytosine derivatives

ABSTRACT

N1-(1,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamides, bearing a lower alkyl, cycloalkyl or cycloalkyl-lower alkyl substituent in the 1-position, prepared by reaction of the corresponding 1substituted-1,2-dihydro-2-oxo-4-aminopyrimidine and N-acylated sulfanilyl chloride with subsequent hydrolysis, are described. The end products are useful as antibacterial agents.

United States Patent Albrecht et al. Dec. 2, 1975 [54] SULFACYTOSINE DERIVATIVES 3,422,098 1/1969 Schmidt et al 260/239.75 lnvgmorsz Harry Allen AlbrechtTOwacmJohn 3,457,278 7/1969 Zimmermannm. 260/239.75

Thomas Plati, Rutherford, both of Ni Primary ExaminerLeonard Schenkman Attorney, Agent, or Firm-Samuel L. Welt; Bernard S. [73] Assignee'. Eojffmann-La Roche Inc., Nutley, Leon; William G. lsgro [22] Filed: June 19, 1974 [57] ABSTRACT A 1 P1 No 480,784 N -(l,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamides,

bearing a lower alkyl, cycloalkyl or cycloalkyl-lower [52] US. Cl 260/239.75; 260/2565 R; 424/229 alkyl substituent in the l-position, prepared by reac- [51] Int. Cl. C07D 239/44 tion of the corresponding l-substituted-l ,2-dihydro-2- [58] Field of Search 260/2565, 239.75 oxo-4-aminopyrimidine and N-acylated sulfanilyl chloride with subsequent hydrolysis, are described. The [56] References Cited end products are useful as antibacterial agents. UNITED STATES PATENTS 5 Claims, No Drawings 3,375,247 3/1968 Doub et al. 260/239.75

SULFACYTOSINE DERIVATIVES BRIEF SUMMARY OF THE INVENTION The invention relates to compounds of the formula wherein R is lower alkyl, cyclo-lower alkyl or cyclolower alkyl-lower alkyl; R is hydrogen or lower alkyl; provided that when R is lower alkyl, then R must be lower alkyl; and salts thereof with pharmaceutically acceptable bases. The compounds of formula I are useful as antibacterial agents.

DETAILED DESCRIPTION OF THE INVENTION The invention relates to compounds of the formula NH'SOZ'X whereinR is lower alkyl, cyclo-lower alkyl or cyclolower alkyl-lower alkyl; R is hydrogen or lower alkyl; provided that when R is lower alkyl, then R must be lower alkyl; and salts thereof with pharmaceutically acceptable bases.

As used herein, the term lower alkyl denotes a straight or branched chain saturated hydrocarbon of l-7 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, neopentyl, pentyl, heptyl, and the like; methyl is preferred. The term cycle-lower alkyl denotes a cyclic hydrocarbon of 3-8 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. The term cyclo-lower alkyl-lower alkyl denotes a lower alkyl group as defined above wherein a hydrogen atom is substituted by a cyclolower alkyl group as defined above. The term alkanoyl denotes a group derived from an aliphatic carboxylic acid of 1-7 carbon atoms, for example, formyl, acetyl, propionyl, and the like.

The compounds of the invention are prepared by reacting a compound of the formula wherein R, and R are as hereinbefore described, with a compound of the formula III wherein R is alkanoyl, and X is chlorine, bromine or iodine, preferably chlorine.

Compounds of formula I, wherein R is hydrogen and R is cyclo-lower alkyl or cyclo-lower alkyl-lower alkyl are a preferred group of compounds. Preferred compounds of formula I are:

pyrimidinyl)-sulfanilamide;

N-( l-cyclopentyl-l ,2-dihydro-2-oxo-4-pyrimidinyl sulfanilamide;

pyrimidinyl)-sulfanilamide;

N l-cyclohexyl-l ,2-dihydro-2-oxo-4-pyrimidinyl)- sulfanilamide;

N l-cyclohexyl-l ,2-dihydro-5 -methyl-2-oxo-4- pyrimidinyl)-sulfanilamide;

pyrimidinyl)-sulfanilamide;

N( l-cyclopropyl-l ,2-dihydro-5-methyl-2-oxoprimidinyl)-sulfanilamide; and the like.

A most preferred compound of formula I of the invention is N-( l -cyclopropyl-l ,2-dihydro-2-oxo-4- pyrimidinyl)-sulfanilamide.

The compounds of formula I form pharmaceutically acceptable acid addition salts with bases. Such bases include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide or the like; or amines such as dicyclohexylamine. .ethylamine, ethanolamine or the like.

The starting materials of formula II are prepared according to the procedures described in the Examples. Exemplary of the compounds of formula II are:

1-cyclopropylmethylcytosine (also known as l-cyclopropylmethyl-l ,2-dihydro-2-oxo-4-aminopyrimidine);

l-cyclopentylcytosine (also known as l-cyclopentyl- 1,2-dihydro-2-oxo-4-aminopyrimidine); l-cyclopropylcytosine (also known as l-cyclopropyll,2-dihydro-2-oxo-4-aminopyrimidine); l-cyclohexylcytos'ine (also known as l-cyclohexyll,2-dihydro-2-oxo-4-aminopyrimidine);

l-cyclohexyl-5-methylcytosine (also known as lcyclohexyl-l ,2-dihydro-5-methyl-2-oxo-4- aminopyrimidine);

l-ethyl-S-methylcytosine (also known as l-ethyl-l ,2-

dihydro-S-methyl-2-oxo-4-aminopyrimidine);

l-cyclopropyl-5-methylcytosine (alsos known as lcyclopropyl-l ,2-dihydro-5-methyl-2-oxo-4- aminopyrimidine); or the like.

The cytosine of formula II is conveniently reacted with a sulfanilyl chloride, -.bromide, or -iodide, preferably the -chloride of formula III in the presence of a base, for example, pyridine, or a trialkylamine such as triethylamine or trimethylamine, with or without an inert organic solvent such as acetonitrile or the like. The reaction temperature is not critical; preferably, the reaction is carried out at room temperature. The result ing product of formula I can be recovered utilizing conventional procedures, for instance, by crystallization or the like.

The N-alkanoyl derivative of formula I, as described in the Examples, can be deacylated according to known procedures. For example, the alkanoyl derivative is treated with an alkali metal hydroxide such as sodium hydroxide. The deacylation is preferably carried out at an elevated temperature, for example, at a temperature in the range of from about 25 to 100C. The reaction product, which is a compound of formula I, can be recovered utilizing conventional procedures, for example, crystallization or the like.

The compounds of formula III are known compounds or can be prepared in accordance with known procedures. Exemplary of such compounds are:

N-acetylsulfanily] chloride;

N-acetylsulfanilyl bromide; or the like.

The compounds of formula I and its pharmaceutically acceptable salts with bases are useful as antibacterial agents, e.g., against S. aureus Smith, S. pyogenes 4, P. vulgaris I and S. typhosa P5 8a. The antibacterial activity of the claimed compounds can be demonstrated in warm-blooded animals, for example, in Swiss albino mice weighing 18 to 20 gms. The mice are infected intraperitoneally with 0.5 ml. of an inoculum containing to 1000 minimal lethal doses of the organism prepared in 5% hog gastric mucin, except for S. pyogenes' 4 which is suspended papain digested bacto beef broth. The infecting inocule are prepared from overnight broth cultures. The test substance is administered orally as follows: two treatments, five hours apart, on the day of and day following infection, and one treatment on the second and third days following infection. Mice which die are autopsied and cultures are taken from heart blood, the survivors are observed for a period of 2 weeks.

For such use, the presently disclosed compounds are formulated, using conventional inert pharmaceutical adjuvant materials, into dosage forms which are suitable for oral or parenteral administration. Such dosage forms include tablets, suspensions, solutions, etc. Furthermore, the compounds of this invention can be embodied into, and administered in the form of, suitable hard or soft capsules. The identity of the inert adjuvant materials which are used in formulating the present compounds into oral and parenteral dosage forms will be immediately apparent to persons skilled in the art. These adjuvant materials, either inorganic organic in nature, include, for example, water, gelatin, lactose, starch, magnesium stearate, talc, vegetable oils, gums, polyalkylene-glycols, etc. Moreover, preservatives, stabilizers, wetting agents, emulsifying agents, salts forv altering osmotic pressure, buffers, etc. can be incorporated, if desired, into such formulations.

The quantity of active medicament which is present in any of the above-described dosage forms is variable. It is preferred, however, to provide capsules or tablets containing from about 100 mg. to about 500 mg. to about 500 mg. of the formula I base or an equivalent amount of a medicinally acceptable base addition salt thereof.

The frequency with which any such dosage form will be administered to a patient will vary, depending upon the quantity of active medicament present therein and the needs and requirements of the patient, as diagnosed by the prescribing physician. Under ordinary circumstances, however, up to about 80 mg/kg. of the compound can be administered daily in several dosages. It is to be understood, however, that the dosages set forth therein are exemplary only and that they do not, to any extent, limit the scope or practice of this invention.

The sulfacytosine derivatives of the invention can also be used in combination with known potentiators of the 2,4-diamino-5-benzylpyrimiding type having the formula u N 5 2 01-1 R n Nl-I N H2N- c11 N 1 wherein R, R, R and R are as defined in formula IV above, and treating the halo compound obtained with ammonia.

The reaction with ammonia is preferably carried out using a lower alkanol as solvent, preferably methanol.

A suitable temperature range is from about 80C. to about 200C., preferably from about 100C. to about 150C. Since said temperature range is above the boiling point of methanol, the reaction is performed in a closed system, e.g., in an autoclave. The chlorinating or brominating step, as the case may be, is performed in the usual manner as known to all persons skilled in the art.

The potentiators of formula IV above may be transformed into pharmaceutically acceptable acidaddition salts by contacting these compounds with suitable acids. Examples of suitable acids are hydrochloricacid, sulfuric acid, phosphoric acid, formic acid, acetic acid, malonic acid, succinic.acid, maleic acid, citric acid, tar- 6 taric acid, malic acid, fumaric acid, methane sulfonic acid or p-toluenesulfonic acid, etc.

Compositions comprising sulfacytosine derivatives and potentiators are prepared by mixing the components, whereby the sulfonamide and the potentiator may be present in a weight by weight ratio of from about 1:] to about 40:1, preferably about 5:1. The mixing of the components may be performed in a known manner. These compositions are useful as antibacterial agents and are administered and used in the same mam ner as described hereinbefore for the compounds of formula I.

Preferred compounds of formula IV are:

2,4-diamino-5-(3,4,5-trimethoxybenzyl)-pyrimidine;

2,4-diamino-5-(4-amino-3,5-dimethoxybenzyl)- pyrimidine; and

2,4-diamino-5-(2-methyl-4,5-dimethoxybenzyl)- pyrimidine.

The following Examples further illustrate the invention. All temperatures are in degrees Centigrade, unless otherwise mentioned.

EXAMPLE 1 Preparation of 3-cyclopropylmethylaminopropionitrile With stirring and cooling in ice to maintain a reaction temperature of 8-10, 16.4 g. of acrylonitrile was added to 22 g. of aminomethylcyclopropane. The mixture was allowed to warm to room temperature, with intermittent cooling for about 1 hour to maintain the temperature below 25, and then allowed to stand overnight. The mixture was heated for one hour on a steam bath and then distilled under reduced pressure to obtain 32.0 g. of 3-cyclopropylmethylaminopropionitrile, boiling at l0l-l02 at 7 mm.

EXAMPLE 2 Preparation of a mixture of l=-( 2-cyanoethyl)- l -cyclopropylmethylurea and l-cyclopropylmethyl-S ,6-dihydrocytosine With cooling in ice to maintain the reaction at 25-30, 19.1 ml. of concentrated hydrochloric acid was added to'29.8 g. of 3-cyclopropylmethylaminopropionitrile to adjust the pH to 6.50. A total of 20.l g. of

' from the hot mixture and washed with an additional 10 ml. of hot isopropanol. The combined filtrate and wash was cooled in ice and allowed to crystallize for 2 hours chamber. The mixture was useddirectly for the preparation of drocytosine.

S-bromo-l-cyclopropylmethyl-5,6-dihy- EXAMPLE 3 Preparation of 1-(2-cyanoethy1 )-1 cyclopropylmethylurea This compound was isolated from the mixture of Ex ample 2 by two recrystallizations from ethanol. This product, which corresponded to the spot at higher Rfs on Tlc, melted at 8487" Analysis Calcd. for: C H N O: C, 57.47; H, 7.84; N, 25.13

Found: c, 57.44; H, 8.01; N, 25.18.

EXAMPLE 4 Preparation of 1 -cyclopropylmethyl-5 ,6-dihydrocytosine EXAMPLE 5 Preparation of 5-bromo-l -cyclopropylmethy1-5 ,6-dihydrocytosine To a solution of 8.10 g. of sodium methoxide in 150 ml. of methanol was added 25.0 g. of the mixture of 1- cyanoethyl- 1 -cyclopropylmethylurea and 1 -cyc1opropylmethyl-S,6-dihydrocytosine obtained in Example 2. The mixture was refluxed for 45 minutes, and then cooled in ice, whereupon crystallization occurred. With stirring and cooling to maintain the reaction at 5, 24.0 g. of bromine was added over a period of 20 minutes. The precipitate redissolved during this addition. The mixture was allowed to warm to room temperature and to stand for 3 days, during which time crystallization occurred. After chilling an ice, the resulting S-bromo- 1 -cyclopropylmethyl-5 ,6-dihydrocytosine was filtered, washed with cold methanol, and dried in a vacuum desiccator over potassium hydroxide; yield 31.1 g., m.p. 139-143 with resolidification. Recrystallization of 30.1 g. of product, from 2.1 of methanol, yielded 17.1 g. of 5-bromo-1-cyc1opropy1methyl-5,6- dihydrocytosine melting at 143-145 with resolidification.

Analysis Calcd. for C H BrN O: C, 39.04; H, 4.91; N, 17.07.

Found: C, 38.91;'H, 4.95; N, 17.03.

EXAMPLE 6 Preparation of 1 cyclopropylmethylcytosine To a solution of 4.55 g. of 85% potassium hydroxide in 93 ml. of methanol cooled to 5, was added 17.0 g. of 5-bromo-1 -cyc1opropylmethyl-5 ,6-dihydrocytosine. The mixture was stirred and allowed to warm spontaneously. When the initial reaction, which had warmed the mixture to 30, subsided, the mixture was refluxed for 5 minutes and allowed to cool and stand at room temperature overnight. The suspension was evaporated under reduced pressure on a water bath at 80. The residue was triturated with 300 ml. of water on a steam bath and chilled in ice before filtering. The resulting 1- cyclopropylmethylcytosine was washed with cold water and dried in a vacuum desiccator over potassium hydroxide; yield, 9.50 g., m.p. 264-266. A sample for analysis was recrystallized from ethanol; m.p. 265267.

Analysis Calcd. for C H N O: C, 58.17; H, 6.71; N, 25.44. Found: C, 58.23; H, 6.39; N, 25.72.

EXAMPLE 7 Preparation of N-Acetyl-N-( 1 -cyclopropylmethyl- 1 ,2-dihydro-2- oxo-4-pyrimidinyl)sulfanilamide A. A mixture of 7.60 g. of l-cyclopropylmethylcytosine, 10.8 g. of N-acetylsulfanilyl chloride and 30 m1. of pyridine was stirred overnight. The mixture was diluted slowly with 300 ml. of water and acidified by addition of 50 ml. of 6N hydrochloric acid. The mixture was allowed to stand for 5 hours to complete the crystallization, before filtering and washing with water; yield 13.5 g. of N-acetyl-N-(1-cyclopropy1methyl-l,2-dihydro- 2-oxo-4-pyrimidiny1)sulfanilamide, m.p. 218-223.

B. A mixture of 495 mg. of l-cyclopropylmethylcytosine, 702 mg. of N-acetylsulfanilyl chloride, 10 m1. of acetonitrile and 322 mg. of triethylamine was stirred and refluxed for 18 hours. The solvent was evaporated under reduced pressure, and the residue triturated with 10 ml. of water and 3 ml. of 10% aqueous sodium hydroxide. The alkaline solution was decanted from the dark insoluble portion and cleared by filtration. Addition of acetic acid to about pH 5 gave a gummy precipitate which solidified only very slowly. The aqueous solution was decanted and the gum triturated with 2 m1. of hot ethanol, and allowed to settle in an ice bath to obtain after filtration 280 mg. of product, melting at 222224. A sample for analysis was recrystallized from aqueous ethanol; m.p. 225226.

Analysis Calcd. for C H N O S: C, 53.03; H, 5.00; N, 15.46. Found: C, 52.94; H, 5.09; N, 15.32.

EXAMPLE 8 Preparation of N-( 1 -cyclopropylmethyl- 1 ,2-dihydro-2-oxo-4- pyrimidinyl)sulfanilamide A mixture of 14.6 g. of N -acetyl-N-( l-cyclopropylmethyl-1 ,2-dihydro-2-oxo-4-pyrimidiny1 )sulfa'nilamide and 146 ml. of 10% aqueous sodium hydroxide was heated on a steam bath for 1 hour after the temperature reached After dilution with 300 ml. of water, the mixture was filtered and acidified to about pH 5 by gradual addition of acetic acid. The initially gummy precipitate quickly solidified. The lumpy solid was crushed, filtered, washed with water, and dried in a vacuum desiccator over potassium hydroxide to yield 10.4 g. of N-( l-cyclopropylmethyl-l ,2-dihydro-2-oxo- 4-pyrimidinyl)sulfanilamide, m.p. 8795. Recrystallization of 10.0 g. of this product from 60 ml. of 50% ethanol and drying in a vacuum desiccator over potassium hydroxide gave hydrated crystals which required further drying at 60 under reduced pressure, yield 8.03 g., m.p. 90-92.

Analysis Calcd. for C H N O S: C, 52.49; H, 5.03; N, 17.49. Found: C, 52.24; H, 5.18; N, 17.32.

9 EXAMPLE 9 Preparation of 3-cyclopentylaminopropionitrile With stirring and cooling in an ice bath to control the temperature at -l5, 36.4 g. of acrylonitrile was added to 58.4 g. of cyclopentylamineover a period of 20 minutes. The mixture was allowed to warm spontaneously to 30, and then cooled intermittently for about 30 minutes, until the reaction subsided. After standing overnight, the mixture was heated for 1 hour on a steam bath and distilled under reduced pressure to yield 82.4 g. of 3-cyclopentylaminopropionitrile, b.p. ll3-l at 9 mm.

EXAMPLE 10 Preparation of 1-(2-cyanoethyl)-1-cyclopentylurea With stirring and cooling to maintain a reaction temperature of 25-30, 45.5 ml. of concentrated hydrochloric acid was added to 76.0 g. of 3-cyclopentylaminopropionitrile to obtain a final pH of 6.50. A total of 46.0 g. of 97% potassium cyanate was then added in 4 equal portions at l-hour intervals. After the first portion was added, the reaction was heated to 50 and maintained at 48-50 with stirring overnight. The mixture was evaporated under reduced pressure with heating on a steam bath. The mixture was twice more evaporated to dryness after the addition of 80 ml. portions of benzene. The residue was triturated with 120 ml. of boiling isopropanol. The potassium chloride was removed by filtration and washed with ml. of hot isopropanol, and the filtrate allowed to crystallize in an ice bath to yield 65 g. of 1-(2-cyanoethyl)-l-cyclopentylurea, m.p. 8l84.

EXAMPLE 1 1 Preparation of 5-bromol -cyclopentyl- 5,6-dihydrocytosine To a solution of 17.8 g. of sodium methoxide in 330 ml. of methanol was added 59.7 g. of l-cyanoethyl-lcyclopentylurea. The mixture was stirred and heated on a steam bath for 30 minutes and then cooled in ice. At 5-8, 52.9 g. of bromine was added over a period of 30 minutes. The ice bath was removed. Thereafter, the mixture was allowed to warm to room temperature and stand for 3 days, during which time crystallization occurred. The mixture was chilled in ice before filtering the product, which was washed with cold methanol and then with ether to yield 69.8 g. of 5-bromo-1-cyclopentyl-5,6-dihydrocytosine, m.p. 134144 with resolidification.

EXAMPLE 12 Preparation of l-cyclopentylcytosine To a solution of 15.8 g. of 85% KOH in 320 ml. of methanol was added at 10, 62.4 g. of 5-brorno-1-cyclopentyl-S,fi-dihydrocytosine. The mixture was stirred temperature, the mixture was evaporated to dryness 110 before filtering to yield 38.8 g. of l-cyclopentylcytosine, m.p. 183198. The product was used directly in the subsequent reaction with N-acetylsulfanilyl chloride.

A sample for analysis was prepared by purification via the hydrochloride, as follows: The l-cyclopentylcytosine (10.0 g.) was dissolved in 40 ml. of warm ethanol, and the mixture strongly acidified by addition of ethanolic l-lCl. The hot solution was cleared by filtra-= tion and allowed to crystallize at room temperature to yield 6.07 g. of l-cyclopentylcytosine hydrochloride, m.p. 204-209. A solution of 5.30 g. of the hydrochloride in 10 ml. of hot water was made strongly alkaline by addition of excess 10% aqueous sodium hydroxide solution, which was allowed to crystallize at room temperature to yield 3.75 g. of l-cyclopentylcytosine, m.p. 229-233.

Analysis Calcd. for C H N O: C, 60.32; H, 7.31; N, 23.45. Found: C, 60.19; H, 7.57; N, 23.64.

EXAMPLE 13 Preparation of N -Acety1-N-( l-cyclopentyl- 1 ,2-dihydro-2-oxo-4- pyrimidinyl )sulfanilamide A mixture of 240 g. of l-cyclopentylcytosine 31.4 g. of N-acetylsulfanilyl chloride and ml. of pyridine was stirred overnight after controlling the initial reaction by momentary cooling to keep the reaction temperature below 35. The mixture was diluted with 800 ml. of water and acidified to pH l-2 by the addition of 148 ml. of 6N hydrochloric acid. After 4 hours, the supernatant liquid was decanted from the viscous gummy precipitate. The gum was dissolved in ml. of warm ethanol and 100 m1. of water was added. The mixture was stirred for 3 hours as crystallization occurred to yield 26.3 g. of N -acetyl-l I-(l-cyc1opentyl-l,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide, m.p. 219-228. The decantate from the initially viscous gummy precipitate also deposited crystals of N-acetyl- N( 1 -cyclopentyl-1 ,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide during three hours; additional yield 2.80 g., m.p. 230234.

EXAMPLE 14 Preparation of N-( l-cyclopentyl-l ,Z-dihydro-2-oxo-4-pyrimidinyl)- sulfanilamide A mixture of 29.1 g. of N-acetyl-N-( l-cyclopentyl- 1 ,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide and 290 ml. of 10% aqueous sodium hydroxide was heated on a steam bath for one hour, diluted with 290 ml. of tap water, and acidified by addition of 60 ml. of acetic acid. The initially oily precipitate solidified over a period of several hours to yield 21.1 g. of product melting over a wide range. The resulting product was dissolved in 200 ml. of boiling methanol. treated with charcoal, and the filtered solution evaporated under reduced pressure to a volume of 65 ml., which crystallized at room temperature .to yield 15.2 g. of N'-(l-cyclopentyl-l ,2-dihydro-2-oxo-4-pyrimidinyl )sulfanilamide', m.p.l67-17l. The product was dissolved in ml.

of methanol. The volume was reduced to 60 ml. by evaporation under reduced pressure, and the product allowed to crystallize at room temperature to yield 12.7 g. of N-( l -cyclopentyl-1 ,2-dihydro-2-oxo-4- pyrimidinyl)sulfanilamide, m.p. l68-171.

Analysis Calcd. for C, H, N O S: C, 53.88; H, 5.43; 1, 16.76. Found: C, 53.78; H, 5.23; N, 16.62.

EXAMPLE Preparation of 3-cyclopropylaminopropionitrile With stirring and cooling to maintain a reaction temerature of l0l5, 46.5 g. of acrylonitrile was added 0 50.0 g. of cyclopropylamine. When the addition was omplete, the reaction mixture was allowed to warm pontaneously to a maximum temperature of 30, and hen allowed to stand overnight at room temperature. tfter heating 1 hour on a steam bath and distillation .nder reduced pressure, 64.8 g. of 3-cycloropylaminopropionitrile, b.p. 9092 at 12 mm., was -btained.

EXAMPLE 16 Preparation of l-(2-cyanoethyl)-l-cyclopropylurea With stirring and cooling in ice, 46 ml. of concenrated hydrochloric acid was added to 64.8 g. of 3- yclopropylaminopropionitrile at -30 to obtain a inal pH of 6.00. A total of 49.3 g. of 97% potassium cynate was then added in 4 portions at intervals of 1 101.11. After the first portion was added, the mixture was larmed to 50 and maintained at 45-50 with stirring wernight. The mixture was evaporated to dryness lnder reduced pressure with warming on a steam bath. \fter the addition of 100 ml. of benzene, the mixture vas again evaporated to dryness. The residue was exracted by trituration with a total of 600 ml. of boiling sopropanol in two portions, and the filtered solution .llowed to crystallize in an ice bath to yield 55.3 g. of -(2-cyanoethyl)-l-cyclopropylurea, m.p. 119123.

EXAMPLE 17 Preparation of S-bromo- 1 -cyclopropyl'5 ,6-dihydrocytosine To a solution of 17.8 g. of sodium methoxide in 330 nl. of methanol was added 50.5 g. of l-(2-cyanoethyl)- -cyclopropylurea. The mixture was refluxed for ninutes, and cooled in ice. With stirring at 46, 52.9 of bromine was added over a period of 30 minutes. ."he mixture, containing some precipitate, was stirred wernight. After approximately 24 hours, a mild exohermic reaction was noted. As the original precipitate uddenly dissolved, a precipitate of white crystals legan to separate. The mixture was allowed to stand or 3 days before filtering, whereby 55.9 g. ofS-bromo- -cyclopropyl-5,6-dihydrocytosine, m.p. 135140 vith resolidification, was obtained.

EXAMPLE 18 Preparation of l-cyclopropylcytosine To a solution of 15.2 g. of 85% potassium hydroxide n 310 ml. of methanol was added 53.3 g. of S-bromo-lyclopropyl-S,6-dihydrocytosine. The mixture was al- Jwed to warm spontaneously for 30 minutes and then efluxed with stirring for 5 minutes. The mixture was tirred for 1.5 hours, allowed to stand overnight, and vaporated under reduced pressure. The residue was issolved in 80 ml. of water at 80, and the solution fter filtration was allowed to crystallize overnight in a efrigerator. The crystallized material was washed with :e-cold water and then with ether to yield 20.4 g. of

-cyclopropylcytosine, m.p. 209-223.

EXAMPLE 19 Preparation of N -Acetyl-N-( l-cyclopropyl-l ,2-dihydro-2-oxo-4- pyrimidinyl )sulfanilamide A mixture of 10.6 g. of l-cyclopropylcytosine, 16.4 g. of N-acetylsulfanilyl chloride and 47 ml. of pyridine was stirred overnight after momentary cooling to maintain the reaction below 30. The mixture was poured into 700 ml. of water, and after filtration by gravity, the solution was strongly acidified by addition of 6N hydrochloric acid. Gradual crystallization occurred overnight in a refrigerator before filtering the N-acetyl-N- 1 -cyclopropyl-l ,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide; yield 10.7 g., m.p. 139-l43.

EXAMPLE 20 Preparation of N-( l-cyclopropyl-l ,2-dihydro-2-oxo-4-pyrimidinyl)- sulfanilamide A solution of 10.7 g. of N-acetyl-N-(l-cyclopropyl- 1,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide in 107 ml. of 10% aqueous sodium hydroxide was heated on a steam bath for 1 hour. After cooling below 35, 15 ml. of acetic acid was added to precipitate a gum, which quickly solidified; yield 7.45 g., m.p. l l9-123. Of this product, 7.35 g. was dissolved in 735 ml. of hot water by adding 12 ml. of 10% aqueous sodium hydroxide to obtain a strongly alkaline solution. After the addition of 5 ml. of acetic acid, the hot solution was immediately filtered and allowed to crystallize at room temperature to yield 5.95 g. of N-(1-cyclopropyl-l,2-dihydro-2- oxo-4-pyrimidinyl)sulfanilamide, m.p. 1241 26.

The sample for analysis, after recrystallization from 80% ethanol, was found to contain water of crystallization.

Analysis Calcd. for C H N O SH O: C, 48.15; H, 4.97; N, 17.28; H O: 5.55. Found: C, 48.01; H, 4.81; N, 17.19; 11 0: 5.96.

EXAMPLE 21 Preparation of 3-cyclohexylaminopropionitrile With stirring and intermittent cooling to maintain the reaction at 2025, 53.0 g. of acrylonitrile was added over a 30-minute period to 99.0 g. of cyclohexylamine. Intermittent cooling was continued for another hour until the reaction subsided, and the mixture was allowed to stand overnight before distillation under reduced pressure to yield 109 g. of 3-cyclohexylaminopropionitrile, b.p. -78 at 0.1 mm.

EXAMPLE 22 Preparation of l-( 2-cyanoethyl)-l -cyclohexylurea With stirring and cooling in ice to maintain the reaction temperature below 35, 57.8 ml. of concentrated hydrochloric acid and 40 ml. of water were added to 106.6 g. of 3-cyclohexylaminopropionitrile, followed by about 3 ml. of 10% aqueous sodium hydroxide to bring the final pH to 6.00. A total of 58.5 g. of 97% potassium cyanate was then added in four equal portions at one hour intervals. After the first addition, the mixture was warmed to 50 and maintained at 45-50 during the remainder of the reaction time. An additional 75 ml. of water was added when a thick precipitate separated, and stirring was continued overnight. The mixture was heated to after adding 200 ml. of water,

and then cooled to room temperature and filtered to yield 121 g. of l-(2-cyanoethyl)-l-cyclohexylurea, m.p. l10-l 12.

EXAMPLE 23 Preparation of -bromo-1-cyclohexyl-5,6-dihydrocytosine To a stirred solution of 27.0 g. of sodium methoxide in 500 ml. of methanol was added 97.5 g. of 1-(2- cyanoethyl)-l-cyclohexylurea. The mixture was refluxed for 30 minutes, cooled to 5, and 80 g. of bromine was added at 5l0 over a period of 30 minutes. The mixture was stirred at ambient temperature overnight, and the precipitate filtered and washed with methanol to yield 118.4 g. of S-bromo-l-cyclohexyl- 5,6-dihydrocytosine, m.p. l52-156 with resolidificatlon.

EXAMPLE 24 Preparation of l-cyclohexylcytosine To a stirred solution of 27.7 g. of 85% potassium hydroxide in 570 ml. of methanol at was added 1 g. of S-bromo-1-cyclohexyl-5,6-dihydrocytosine. The mixture was allowed to warm spontaneously, reaching a maximum temperature of 33? after 13 minutes. After about 1 hour, the mixture was refluxed for 5 minutes and allowed to cool to room temperature with continued stirring for 2 hours. After standing overnight, the mixture was evaporated under reduced pressure. The residue was triturated with 500 ml. of water at 75 for 5 minutes and allowed to settle for 2 hours with cooling in ice to yield 70.7 g. of a product, m.p. 213231. Of this product, 65.0 g. was recrystallized from 375 ml. of methanol to yield 42.7 g. of l-cyclohexylcytosine, m.p. 252-25 8.

EXAMPLE 25 Preparation of N"-Acetyl-N-( 1 -cyclohexyl-1 ,2-dihydro-2-oxo-4- pyrimidinyl)sulfanilamide A mixture of 29.0 g. of l-cyclohexylcytosine, 90 ml. of pyridine and 35.1 g. of N-acetylsulfanilyl chloride was stirred overnight, poured into 900 ml. of water, and acidified by addition of 80 ml. of concentrated hydrochloric acid. After several hours of vigorous stirring, the precipitated product solidified to yield 33.3 g. of N-acetyl-N-( l-cyclohexyl-l ,2-dihydro-2-oxo-4- pyrimidinyl)sulfanilamide, m.p. 219234. A sample purified by two recrystallizations from ethanol melted at 247250.

EXAMPLE 26 Preparation of N-( l-cyclohexyl-l ,2-dihydro-2-oxo-4-pyrimidinyl )sulfanilamide A mixture of 27.9 g. of N"-acetyl-N-(l-cyclohexyl- 1,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide and 280 ml. of 10% aqueous sodium hydroxide was stirred and heated on a steam bath for 1 hour, diluted with 280 ml. of water, cooled to room temperature, and acidified by dropwise addition of 56 ml. of acetic acid to precipitate a finely divided solid to yield 21.4 g. of crude N- (l-cyclohexyll ,2-dihydro-2-oxo-4-pyrimidinyl )sulfanilamide, m.p. 100-120.

Dicyclohexylamine Salt 0f the product, 20.0 g. was dissolved in 120 ml. of hot ethanol and 11.5 g. of dicyclohexylamine was added. The hot solution was filtered quickly and then crystallization was allowed to proceed first at room temperature and then in a refrigerator overnight to yield 15.8 g. of the dicyclohexylamine salt of N -(lcyclohexyl-l ,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide, m.p. 126l28. A sample for analysis was recrystallized from ethanol; it contained ethanol of crystallization.

Analysis Caled. for C H N O S (C H N O S tl H N C H O) C, 62.58; H, 8.58; N, 12.16.

Found: C, 62.34; H, 8.54; N, 12.23.

Of the above dicyclohexylamine salt, 15.5 g. was stirred with 300 ml. of water, ml. of 10% aqueous sodium hydroxide and 250 ml. of ether. The ether was separated, and the aqueous phase washed again with 250 ml. of ether. The aqueous solution was diluted and 1200 ml. of water, heated to quickly acidified with 15 ml. of acetic acid, and allowed to stand 3 days before filtering the precipitate to yield 8.50 g. of N-( 1- cy'clohexyl-l ,Z-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide, m.p. 153156. This product was dissolved in 60 ml. of hot methanol, and the solution filtered and boiled down to a volume of 25 ml. before allowing to stand and crystallize overnight to yield 7.10 g. of N-( 1- cyclohexyl- 1 ,2-dihydro-2-oxo-4-pyrimidinyl)sulfanilamide, m.p. l55-l57.

Analysis Calcd. for C l-l N O S: C, 55.16; H, 5.79; N, 16.08.

Found: C, 54.94; H, 5.82; N, 16.36.

EXAMPLE 27 Preparation of 1-cyclohexyl-4-thiothymine A solution of 8.20 g. of l-cyclohexylthymine and 9.60 g. of phosphorous pentasulfide in 500 ml. of pyridine was refluxed for 9 hours, and the solvent distilled off under reduced pressure. The residue was triturated with 120 ml. of water to obtain a solid, which was dried in the air and recrystallized from 120 ml. of ethanol to yield 7.15 g. of 1-cyclohexyl-4-thiothymine, melting at 176179. glggglqano, S, Goya and T. Takahashi, J, Pharm. Soc. Japan, 88, l 112 A 300 mg. sample of product prepared as above was recrystallized from 6 ml. of ethanol to obtain 224 mg. of analytically pure l-cyclohexyl-4-thiothymine, melting at 177l78.

EXAMPLE 28 Preparation of 1-cyclohexyl-5-methy1cytosine 5.0 g. of 1-cyclohexyl-4-thiothymine was added to 120 ml. of ethanol which had been saturated with ammonia at 5. The solution was heated under pressure at 120 for 22 hours. After removal from the pressure reactor, the mixture was reheated, filtered and concentrated by evaporation under reduced pressure to a volume of 60 ml. The solution was chilled in ice to obtain 3.28 g. of crystalline product. On further concentration, the mother liquor yielded a second crop of 0.69 g. The combined crops, which contained ethanol of crystallization, were distilled with m1. of toluene until approximately 50 ml. of distillate was collected. The residue was chilled in ice to obtain 2.65 g. of lcyclohexyl-S-methylcytosine, melting at 205-207.

EXAMPLE 29 Preparation of N-acetyl-N-(1-cyclohexyl-1,2-dihydro-5-methyl-2- oxo-4-pyrimidinyl)sulfanilamide A mixture of 2.07 g. of 1-cyclohexyl-5-methylcytosine, 10 ml. of pyridine and 2.34 g. of N-acetylsulfanilyl chloride was stirred overnight, poured into 100 ml. of cold water, and acidified by addition of 18 ml. of 6N hydrochloric acid. Supernatant liquid was decanted from the gummy precipitate, which was washed with water, by decantation. The gun solidified on trituration with 10 ml. of ethanol to yield 1.75 g. of N-acetyl-N (l-cyclohexyl-l ,2-dihydro- -methyl-2-oxo-4- pyrimidinyl)sulfanilamide, melting at 254-256. The product may be crystallized from ethanol.

EXAMPLE 30 Preparation of N l-cyclohexyl-l ,2-dihydro-5-methyl-2-oxo-4- pyrimidinyl) sulfanilamide A mixture of 169 mg. of N -acetyl-N-( l-cyclohexyl- 1,2-dihydro-5-methyl-2-oxo-4-pyrimidinyl)sulfanilamide and 1.7 ml. of aqueous sodium hydroxide was heated on the steam bath for 30 minutes, diluted with an equal volume of water, and heated for another 30 minutes. The mixture was cooled and acidified by dropwise addition of acetic acid, diluted with 1 ml. of water and allowed to stand for 30 minutes before filtering. Of the crude product obtained (123 mg.), 94 mg. was dissolved in 2 ml. of warm methanol, and crystallized by evaporating to one-quarter volume in a stream of nitrogen, to obtain 48.9 mg. of N 1-cyclohexyl-1,2- dihydro-5-methyl-2-oxo-4-pyrimidinyl)sulfanilamide, melting point 203-206.

EXAMPLE 31 Preparation of 1-ethyl-4-thiothymine A mixture of 4.62 g. of 1-ethylthymine 7.33 g. of phosphorus pentasulfide and 100 ml. of pyridine was refluxed for 8.5 hours. The pyridine was distilled off under reduced pressure, and the residue triturated with 50 ml. of water to obtain a solid, which was filtered and washed with four 10 ml. portions of water. After drying in the air, this material was crystallized from 100 ml. of ethanol to obtain 4.00 g. of 1-ethyl-4-thiothymine, melting at 204-207. 2K. Yamauchi and M. Kinoshita, J. Chem. Soc. Perkin 1, 1973.391.

EXAMPLE 32 Preparation of l-ethyl-5-methylcytosine 3.40 g. of 1-ethyl-4-thiothymine was added to 100 ml. of ethanol which had been saturated with ammonia at 5. The solution was heated under pressure at 120 for 24 hours. The mixture was cooled in ice, and the crystalline product filtered and washed with cold ethanol to obtain 2.00 g. of 1-ethyl-5-methyl cytosine, melting at 244-247.

The melting point was unchanged when a sample for analysis was prepared by recrystallization from ethanol.

EXAMPLE 33 Preparation of N -acetyl-N 1 -ethyl-1 ,2-dihydro-5-methyl-2-oxo-4- pyrimidinyl) sulfanilamide A mixture of 1.53 g. of 1-ethyl-5-methylcytosine, 2.34 g. of N-acetylsulfanilyl chloride and 10 ml. of pyridine was stirred overnight, diluted with 100 ml. of cold water, filtered with a little l-lyflo to remove turbidity and acidified by addition of 19 ml. of 6N hydrochloric acid. The product was allowed to crystallize for several hours at room temperature before filtering, washing with water, and drying in a vacuum desiccator over potassium hydroxide to obtain 1.78 g. of N -acetyl-N-( lethyl-1,2-dihydro-5-methyl-4-pyrimidinyl)sulfanilamide, melting at 235 239".

EXAMPLE 34 Preparation of N-(1 ethyl-l,2-dihydro-5-methyl-2-oxo-4-pyrimidinyl) sulfanilamide A mixture of 1.00 g. of N -acetyl-N -(l-ethyl-l,2 dihydro-S-methyl-2-oxo-4-pyrimidinyl)sulfanilamide and 10 ml. of 10% aqueous sodium hydroxide was heated for one hour on the steam bath, diluted with ml. of water, cooled and acidified by gradual addition of acetic acid. The solid precipitate was filtered and washed with water to obtain 0.72 g. of product melting at 174-176. Recrystallization of 0.50 g. of this product from ml. of ethanol gave 0.35 g. of N-( l-ethyl- 1,2-dihydro-5-methyl-2-oxo-4-pyrimidinyl)sulfanilamide, melting at 176l78.

EXAMPLE 35 Preparation of 1-cyclopropyl-4-thiothymine 10.24 g. of ethyl (2-methyl-3-piperidino-thioacryloyl)-carbamate were added with stirring to a solution of 2.52 g. of cyclopropylamine in ml. of ethanol. The mixture was cooled slightly to keep the temperature below 32 when the product rapidly crystallized. After 30 minutes, the mixture was chilled in ice and filtered, to obtain 5.45 g. of l-cyclopropyl-4-thiothymine, melting at 178l80. R. w. Lamon, J. Het. Chem., 5. 837 (1968).

A sample for analysis was obtained by recrystallization from ethanol. The melting point was unchanged.

EXAMPLE 36 Preparation of 1-cyclopropyl-5-methylcytosine 7.50 g. of 1-cyclopropyl-4-thiothymine was added to 120 ml. of ethanol which had been saturated with ammonia at 5. The solution was heated under pressure at 120 for 22 hours. The mixture was cooled in ice and the crystals filtered and washed with cold ethanol to obtain 5.33 g. of 1-cyclopropyl-5-methylcytosine, melting at 252256. Y

A sample obtained for analysis by recrystallization from ethanol melted at 253255.

EXAMPLE 37 Preparation of N-acetyl-N-( l-cyclopropyl-l ,2-dihydro-5-methyl-2- oxo-4pyrimidinyl)sulfanilamide A mixture of 0.83 g. of l-cyclopropyl S-methylcytosine, 1.17 g. of N-acetylsulfanilyl chloride and 4 ml. of pyridine -was stirred overnight, diluted with ml. of

2-oxo-4-pyrimidinyl)sulfanilamide, melting at l76l8l. H

EXAMPLE 38 Preparation of N l-cyclopropyl-1,2-dihydror-mcthyl- 2-oxo-4- pyrimidinyl) sulfanilamide.

A mixture of 500 mg. of N -acety1-N-(1-cyc1opropyl-l ,2-dihydro-5-methyl-2-oxo-4-pyrimidiny1)sulfanilamide and 5 ml. of aqueous sodium hydroxide was heated on the steam bath for 1 hour, diluted with 10 ml. of water, cooled and acidified by gradual addition of 1 ml. of acetic acid. The initial oily precipitate quickly solidified and filtration gave 332 mg. of product melting at 128133. Recrystallization from 7 ml. of ethanol gave 120 mg. of N-cyclopropyll,2-dihydro- N-( l-cyclohexyl-l ,2-dihydro-2-oxo-4-pyrimidinyl)- sulfanilamide is mixed with lactose and corn starch in a suitable mixer. The mixter is further blended by passing through a Fitzpatrick Comminuting Machine with a No. 1A screen with knives forward. The blended powder is returned to the mixer, the talc is added and blended thoroughly. The mixture is filled into No. 4 hard shell gelatin capsules on a Parke Davis capsulating machine.

EXAMPLE 40 Procedure:

Tablet Formulation Per Tablet N-( l-cyclohexyl-l ,2-dihydro-2-oxo-4- pyrimidinyllsulfanilamide (2% excess) 255 mg. Dicalcium Phosphate Dihydrate. Unmilled 230 mg. Corn Starch 70 mg. FD&C Yellow No.5 Aluminum Lake 25% 2 mg. Durkee 117 25 mg. Calcium Stearate 3 mg. Total Weight 585 mg.

Mixture of diand tri- C C fatty acid esters of glycerin (primarily srearic acid with smaller amounts of palmitic and oleic acids).

All the ingredients are mixed thoroughly and Fitzed (Model D) using a No. 1A screen, medium speed. The mixture is remixed and slugged. The slugs are screened on an Oscillator through a No. 14 mesh screen and compressed on an 13" machine.

EXAMPLE 41 Tablet Formulation mg/tab.

N-( l-cyclohexyl- 1 ,2-dihydro-2-oxo-4- pyrimidinyl)sulfanilamide 400 2,4-diamino-5-(3,4,5-trimethoxybenzyl)- pyrimidine Mierocrystalline Cellulose PH 102 75 Corn Starch, Dried 10 Methylcellulose 400 cps 9 Microcrystalline Cellulose PH 1 102 75 Corn Starch, Dried 40 Magnesium Stearate 2 Total Tablet Weight 691 Procedure:

N-( l-cyclohexyl-l ,2-dihyro-2-oxo-4-pyrimidinyl)- sulfanilamide and 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidines are mixed together in a suitable blender. The mixture is milled through a Fitzmill using No. 1 plate, hammers forward, high speed. The resulting mixture is granulated with the 5% methylcellulose solution in distilled water and aged overnight in a refrigerator. The wet granulation is passed through a No. 5 screen, hammers forward, low speed, and dried overnight in a suitable oven at F. The dried granulation is then milled through No. 2A plate, hammers forward, low speed. The microcystalline cellulose Ph 1102 and the dried corn starch are milled through a No. 1 screen, hammers forward, medium speed. The materials from the last two steps are mixed for 10 minutes in a suitable blender. The magnesium stearate is added to the above mixture and mixed for 2 minutes. The resulting material is then compressed into tablets having a weight of 691 mg. per tablet.

pyrimidinyl)sulfanilamide and 2,4-diamino-5-(3,4,5- trimethoxybenzyl)pyrimidine are mixed together in a suitable mixer for 10 minutes. The resulting mixture is milled through a No. 1A plate, knives forward, medium speed, Fitzmill. The mixture from the foregoing step is granulated with distilled water. The resulting granulation is passed through a No. 5 screen, knives forward, slow speed, Fitzmill. The granulation is racked and oven dried at 120F overnight. The dried granulation is passed through a No. 12 wire mesh screen on a Fitzmill at low speed, knives forward. Thereafter, the primojel and magnesium stearate are added, and the resulting mixture mixed for 5 minutes. The granulation is pressed at 1,065 mg. on a suitable rotary tablet press.

We claim: 1

1. A compound of the formula H acceptable salt thereof. Y 2. The compound of claim I which is N-l-cyclo NHSO IN H propylmethyl-l ,Z-dihydro-2-oxo-4-pyrimidinyl)-sulfanilamide.

I 3. The compound of claim 1 which is N-(l-cyclopentyl-l ,2-dihydro-2-oxo-4-pyrimidinyl )-sulfanilal mide. l0 4. The compound of claim 1 which is N-( l-cyclopropyl-l ,2-dihydro-2-oxo-4-pyrimidinyl)-sulfanilamide.

5. The compound of claim 1 which is N-( l-cyclohexwherem 1 18 cycle-lower alkyl or cycle-lower y yl-l,2-dihydro-2-oxo4-pyrimidinyl)-sulfanilamide. lower alkyl and R is hydrogen; or a pharmaceutically UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION IATENT NO. 3,792

DATED December 2, 1975 INVENTO R(S) I Harry Allen Albrecht & John Thomas Plati It is certified that error appears rrr the ab0ve-identified patent and that said Letters Patent are hereby corrected as shown below: C

Column 20, claim 2, "N 1cyc1o" should be:

1 N (lcyc10 firgne and Sealed {has eleventh of May 1976 ISEAL] Anesr: Or I RUTH C. MASON C. MARSHALL DANN irnsrmg ()ffiflf ('ummisxr'uncr nj'lalcnls and Trademarks 

1. A COMPOUND OF THE FORMULA
 2. The compound of claim 1 which is N1-1-cyclopropylmethyl-1,2-dihydro-2-oxo-4-pyrimidinyl)-sulfanilamide.
 3. The compound of claim 1 which is N1-(1-cyclopentyl-1,2-dihydro-2-oxo-4-pyrimidinyl)-sulfanilamide.
 4. The compound of claim 1 which is N1-(1-cyclopropyl-1,2-dihydro-2-oxo-4-pyrimidinyl)-sulfanilamide.
 5. The compound of claim 1 which is N1-(1-cyclohexyl-1,2-dihydro-2-oxo-4-pyrimidinyl)-sulfanilamide. 